I grafted the changeset to stable here:
http://hg.savannah.gnu.org/hgweb/octave/rev/beb43248d602

Closing as fixed.

Confirmed eith Ovave 4.4.0 pn Win-7.
But it also crash in 4.2.2, so for me it is not a regression

Here is a reproducible way to generate a CRASH with Octave 4.3.92 under linux as well as under Windows:

• Download the appended text file. I just contains an example text with the three letters abc. The text encoding (generated with Geany) is "UTF 16 BE with BOM", some other text editor called this "ucs big endian".
• run the following easy code to import this text file with the textscan function:

filename ='text_ucs-big.csv'
fid=fopen(dateiname);
a_textscan = textscan(fid,'%s');
##fclose(fid);
##a_textscan{1}

This still worked fine with Octave 4.2.1 (i.e. no crash). So this is a regression.

I don't know if the chosen text encoding is the only one to produce a crash. I testes around 5 different text encodings (for a different bug report), and those worked fine.